How to charge 2 batteries at once (what to buy)

[rdcrds]

i run through 3 batteries a day on average when i cant charge my phone. i tried to look on ebay but i couldnt figure it out. what would i need to buy to charge 2 batteries outside of the phone at once? do i really have to buy 2 of those battery only chargers or is there something that can do 2 at once?